Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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423 FXUS62 KCHS 031414 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1014 AM EDT Wed Jul 3 2024 .SYNOPSIS... A weak front will linger near the area today. Through the rest of the week, a hot and humid air mass will build over the region. A weak cold front could approach the region by early next week. && .NEAR TERM /THROUGH TONIGHT/... The satellite GOES Water Vapor product showed a mid-level ridge centered over the Deep South with a plume of moisture across SE SC/GA. KCLX detected isolated to scattered showers across coastal waters this morning, this activity should drift east through the rest of this morning east of an old land breeze. The sfc pattern across the forecast area today should feature a ridge along the Carolina coast as a stationary front / trough remains over SE GA. By early this afternoon, a sea breeze is expected to develop, drifting inland through the rest of this afternoon and evening. The 12z observed KCHS sounding indicated poor low and mid-level lapse rates with meager instability. However, recent runs of HRRR and RAP indicate that a field of weak instability will remain across the stationary front across SE GA this afternoon. The combination of weak moisture convergence within the trough/stationary front and development of the sea breeze should trigger isolated showers and thunderstorms across SE GA this afternoon. Given the timing of the sea breeze, high temperatures are forecast to range from the low 90s inland to the mid to upper 80s along the coast. Tonight: Overall, a quiet night is expected as see little to no overnight convection. The boundary we have been dealing with for the last few days will no longer be present and we carry a dry forecast for the forecast area. Look for lows in the low to mid 70s. && .SHORT TERM /THURSDAY THROUGH SATURDAY/... A mid level ridge will extend across the region late week into the weekend. A closed low over the Atlantic will drift westward towards the Southeast coast late. The surface pattern will largely feature high pressure offshore and trough of low pressure inland. A weak front will approach the region on Saturday but will stay well west of the local area. The weather should be fairly quiet for Independence Day and Friday with influence of the ridge helping to limit convection. Just isolated showers and thunderstorms are forecast. Saturday should be a bit more convectively active, especially inland, with better instability and possibly some weak upper support. There could be development with the sea breeze, but it appears most will trigger off the inland trough and then move into the local area from the west. Rain chances peaking 40-50% in these locations seems reasonable. Temperatures will rise with time. Highs in the low to mid 90s Thursday will warm to the mid to upper 90s away from the immediate coast for Friday and Saturday. It will feel even hotter with heat indices approaching the local Heat Advisory criteria of 108 in spots. Friday looks more marginal, with Saturday having the better chance for excessive heat headlines. Lows average in the mid to upper 70s. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... Ridging generally prevails aloft early next week in between a mid level trough to the west and closed low over the Atlantic which should eventually weaken. Surface pattern maintains high pressure offshore and troughing inland. Guidance indicates PWats exceeding 2 inches through much of the period. At least scattered showers and thunderstorms will be possible each day, with highest coverage in the afternoon and evenings. Temperatures are forecast to stay slightly above normal. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... Prior to the 12z TAFs, KCLX detected scattered showers along the coast and across the adjacent Atlantic waters. These showers appeared focused along and east of a land breeze. The convection should remain a considerable distance from the terminals this morning. Heating this morning may develop cumulus with bases between 030-040 kft. Cloud based should rise well into VFR ranges this afternoon. Generally, winds through the TAF period should remain from the east between 5 to 10 kts. Extended Aviation Outlook: Brief flight restrictions are possible in showers and thunderstorms, mainly in the afternoon and evenings through the period. && .MARINE... Today and tonight: North-northeast flow should prevail across the local waters through the period. Wind should be strongest today, focused along the coast with the development of the afternoon sea breeze. Speeds should mostly be 10-15 knots, with gusts up to 20 knots along the coast. Overnight, speeds should drop off to 5-10 knots late. Seas are expected to average 2-4 feet. Thursday through Monday: Northeast/east winds initially will turn southerly by late week. Marine conditions should stay solidly below small craft advisory criteria with speeds 15 knots or less and seas averaging 2-3 feet. Rip currents: Longer period swell and the approaching new moon will lead to an elevated risk for rip currents on Thursday. Local calculations give borderline low-moderate risk, but given the Independence Day holiday, opted for moderate. && .TIDES/COASTAL FLOODING... Onshore winds and the approach of the new moon will lead to elevated tides over the next couple of days along the Charleston and Colleton county coasts. Tides levels could approach minor coastal flooding criteria of 7 ft MLLW in the Charleston Harbor with the evening high tides today and Thursday. Further south, no tide issues are expected. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...NED SHORT TERM...ETM LONG TERM...ETM AVIATION...NED MARINE...BSH/ETM